A theoretical potential energy surface study of several states of the methoxy radical

Several low-lying potential energy surfaces of the methoxy radical have been studied at C3v conformations using ab initio quantum chemical techniques. A double-zeta quality basis set augmented with polarization and diffuse functions has been used throughout. Eight doublet and quartet states have been characterized as a function of C–O distance. The equilibrium conformation of the 2E ground state is found (RCO = 1.405 Å, RCH = 1.112 Å, ϑHCO = 111.3°), and the harmonic vibrational frequencies of the three a1 modes are calculated (3118, 1330, and 1017 cm−1). The ? 2A1←? 2E vertical excitation energy has been estimated to be 4.01 eV. The wave functions for the ? and ? states have been analyzed in terms of their dipole moments, population analyses, and orbital contour plots.